Re: [microblaze-uclinux] Re: [PATCH 1/2] microblaze: add stack unwinder

[Michal Simek]

Steven J. Magnani wrote:
> On Fri, 2010-04-16 at 10:32 +0200, Michal Simek wrote:
> > Please apply this patch and do the same testing as I did.
> >
> > diff --git a/arch/microblaze/kernel/reset.c b/arch/microblaze/kernel/reset.c
> > index a1721a3..76f6587 100644
> > --- a/arch/microblaze/kernel/reset.c
> > +++ b/arch/microblaze/kernel/reset.c
> > @@ -112,8 +112,8 @@ void of_platform_reset_gpio_probe(void)
> >   void machine_restart(char *cmd)
> >   {
> >          printk(KERN_NOTICE "Machine restart...\n");
> > +       machine_shutdown();
> >          gpio_system_reset();
> > -       dump_stack();
> >          while (1)
> >                  ;
> >   }
> > @@ -121,6 +121,7 @@ void machine_restart(char *cmd)
> >   void machine_shutdown(void)
> >   {
> >          printk(KERN_NOTICE "Machine shutdown...\n");
> > +       dump_stack();
> >          while (1)
> >                  ;
> >   }
>
> I get this:
>
> Call Trace:
> [<20003008>] microblaze_unwind+0x68/0x94
> [<20002c24>] show_stack+0x134/0x174
> [<20002c80>] dump_stack+0x1c/0x3c
> [<20001d84>] machine_shutdown+0x30/0x40
> [<20001dc0>] machine_restart+0x2c/0x48
> [<2002a540>] kernel_restart+0x5c/0x80
> [<2002a6b8>] sys_reboot+0x11c/0x218
> SYSCALL
> [<2d5c0248>] PID 118 [reboot]
>
> Is your problem on a MMU or noMMU system?

Interesting. It was noMMU system.

> If the unwinder stops early, it found a return address outside the
> kernel text, or couldn't find the addik that creates a stack frame - but
> there's not enough information here to tell what happened. In your case
> the backtrace goes off the rails before getting to the frame for
> dump_stack(), which is where the stack dump begins. We'd need to see the
> 21 words preceding the dump (show_stack's frame is 13 words, and
> microblaze_unwind's is 8) to know why.
>
> Can you uncomment the #define DEBUG in unwind.c and try it again?

will do next week and let you know.

Thanks,
Michal


> Thanks,
> ------------------------------------------------------------------------
>  Steven J. Magnani               "I claim this network for MARS!
>  www.digidescorp.com              Earthling, return my space modulator!"
>
>  #include <standard.disclaimer>
>
>
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--
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
Microblaze U-BOOT custodian
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